Portioning and packaging apparatuses and methods, in particular for the production of sausages, have long been known. The conveyor device thereof, the so-called filling material or, briefly, filler, has a generally funnel-shaped filling and supply container for the generally liquid, pasty and/or granular filling material (sausage meat, sealing material, explosive or the like). The filling material is expelled by means of an extruder through the filling tube into the packaging case which is closed at one end and in so doing pulls it off the filling tube. A filler control system provides for accurate portioning, the filler control system actuating the extruder for conveying a predetermined portion size and then stopping it. At the beginning of what is referred to as the clipping pause in which the filler is stationary, the filler control system outputs a control pulse to a control device of the closure device, which actuates same for carrying out a selected working cycle.
The working cycle of the closure device or clip machine includes the step of engaging into the filled packaging case by means of at least two pairs of oppositely movable constriction means or displacement members in order to locally constrict the case to form a tube end plait portion. Thereafter the constriction means are typically spread axially with respect to the tubular case in order to extend the length of the tube end plait portion. Then one or two closure elements (clips) are fitted onto the tube end plait portion and shaped therearound until the case is closed with the required level of strength, by means of closure tools which are also oppositely movable (punch and die). The packaging case can be severed selectively between the two closure elements by means of a blade in order to produce individual sausages or lines of sausages of the desired length. The constriction means and the closure tools then open again and move back into their starting position (open position). The working cycle is concluded. The speed, moments in time and/or travel distances of the individual working steps can be optimally adjusted on the basis of a product selection to the nature and the diameter of the associated packaging material by an operator by means of the closure machine control system.
A second kind of closure apparatus is also known. Besides those with spreading displacement in which the displacer elements are moved axially away from each other after the constriction operation in order to extend the length of the constriction region for fitting the clips, DE 101 31 807, also published as U.S. Pat. No. 6,871,474, discloses a closure apparatus which dispenses with the formation of a tube end plait portion of increased length, to the advantage of simpler kinematics. That kind of closure apparatus can operate at a substantially higher cycle rate by virtue of the simpler kinematics.
The cycle rate however hits limits in respect of the filling device as that device cannot start and stop just as rapidly as may be desired, inter alia in dependence on the viscosity of the filling material.